History

Percy Raymond

The landmark discoveries and extensive field work of Charles Walcott were followed up immediately by the research of another American palaeontologist, Percy Raymond. He visited the Burgess Shale three times in the mid-1920s, opened a new quarry in 1930, and established a substantial research and teaching collection at Harvard University.

Background

By the middle of the 1920s, Walcott's discovery of the Burgess Shale was already well known to the scientific community and the wider public. The proximity of a Parks Canada trail (which undoubtedly had facilitated Walcott's discovery) made the Burgess Shale an attractive destination for tourists, teachers, and students. This trail, originally established in the early 20th century, is still being used today.

Amongst the many new visitors to the site was Percy Raymond, a curator of Paleontology at Harvard's Museum of Comparative Zoology. Raymond had been assistant curator at the Carnegie Museum (1904-1910) and the Geological Survey of Canada's chief paleontologist (1910-1912) before moving to Harvard where he worked until his retirement in 1945.

1920 Publication

Raymond was a leading expert on trilobites who had already written general discussions on the limbs of trilobites and other arthropods from the Burgess Shale as early as 1920 (based on Walcott's publications). This 1920 paper also offered one of the first reconstructions of a complete Burgess Shale organism ever published (Marrella splendens). This practice is common today in research papers, but at the time was novel and allowed the non-specialist to clearly see features of the organisms in the same way they would see features in drawings of modern organisms. (With the exception of a few drawings published posthumously in 1931 by his assistant Charles Resser, Walcott never published a reconstruction of a Burgess Shale organism.)

First Visits to the Burgess Shale: mid-1920s

Walcott Quarry from the southeast in 1924 showing Percy Raymond (in middle) with Tom Clarke (Assistant Professor in the Department
of Geology at McGill University) (right) and an unidentified person (left).

Photographer unknown. (Image courtesy Desmond Collins)

Raymond led several summer courses to the Canadian Rockies, visiting the Burgess Shale with his students in 1924, 1925, and 1927. During his
early visits, Raymond collected a few fossils from loose slabs along the slopes below what has come to be known as the Walcott Quarry, and
others from the Trilobite Beds on Mount Stephen. One of these specimens turned out to be a new sponge called
Petaloptyon.

Holotype of Petaloptyon danei from the Trilobite Beds, discovered by Percy Raymond from the Trilobite Beds.

At the Walcott Quarry: 1930

In 1930 Parks Canada gave Raymond permission to re-open the Walcott Quarry. Raymond (with three assistants) spent more than two weeks at the quarry that year, excavating hundreds of fossils and demonstrating the fossil beds were still productive (despite Walcott's own view that he had almost exhausted the quarry as early as 1918.)

Opening Raymond's Quarry: 1930

Perhaps more importantly, Raymond noted the presence of a second fossiliferous bed higher up on the mountain, about 22
metres (72 feet) above the Walcott Quarry. Raymond was not the actual discoverer of these fossiliferous beds – Walcott had
collected several fossils from there (and even sketched some), like the sponge Vauxia. But
Raymond quarried these beds more extensively, uncovering additional Vauxia specimens as
well as Ottoia, Leanchoilia, and Sidneyia. This second
quarry is now known as Raymond's Quarry — but the limits of the original quarry have been lost due to subsequent excavations
by the GSC and ROM at the same levels.

Raymond's specimens showed Burgess Shale-type fossils could be found beyond the famous Walcott Quarry and at various stratigraphic intervals, including in the Mount Stephen Trilobite Beds. Indeed, new Burgess shale-type deposits have since been discovered as far away as China, Greenland, and Australia.

The Collection at Harvard University

Raymond collected more than a thousand fossils from the Burgess Shale (mostly from the Walcott Quarry), and while that paled in comparison to the 65,000 collected by Walcott, it did ensure Harvard had the second-largest collection of Burgess Shale fossils in the world at the time. Based on the newly-collected specimens, Raymond redescribed Leanchoilia superlata and published the first reconstruction of the animal in 1935. Surprisingly, Raymond's collection (like Walcott's) was largely ignored until the 1960s and few researchers made use of the fossils during this time.

Leanchoilia superlata reconstructed by Raymond (1935), and a specimen that Raymond collected from the Burgess Shale (MCZ 5962) - this particular specimen belongs now to L. persephone.

Post-Raymond, Franco Rasetti and the Burgess Shale trilobites

The next scientifically-significant visitor to the Burgess Shale was a famous physicist turned paleontologist. Franco Rasetti had immigrated to Canada from Italy in 1939 to take the chair in Physics at Laval University, Quebec. Rasetti had been part of an influential group of scientists headed by Enrico Fermi before the Second World War and helped work out the basics of atomic fission. Fermi went on to help develop the first atomic bomb, but Rasetti chose to take a job at Laval in Quebec because he did not want to be involved in war-related research. Even as he helped establish Laval's Physics Department, he became increasingly interested in botany and paleontology, particularly trilobites. A former student recalled that Rasetti looked for trilobite fossils "everywhere", collecting thousands of specimens which he carefully classified and described.

During two field expeditions in 1947 and 1948, Rasetti systematically collected many trilobites from the Stephen Formation and other Middle Cambrian rocks in the southern Canadian Rockies. His accounts of these trilobites were published in the Smithsonian Miscellaneous Collections in 1951 and still represent the only major regional reference on these fossils.

Trilobites are valuable to paleontologists because they are good biostratigraphic indicators: they tend to be common fossils, to be distributed widely and to evolve comparatively quickly. Using trilobites as markers allows researchers to determine that different rock units, even if they are widely separated from each other, have a similar age if they have a similar combination of trilobite species.

Prior to Rasetti's work, Deiss (1939) had proposed the Bathyuriscus-Elrathina Zone, named after two trilobites found in Middle Cambrian rock units present in North America. These trilobites are common in the Burgess Shale, placing the relative age of the Stephen Formation in the Middle Cambrian. Rasetti established a number of additional trilobite zones and "faunules" subdividing the Stephen Formation into smaller relative time slices, which proved useful in later stratigraphic studies.